1. Field of the Invention
The invention relates to a process for the manufacture and purification of methyl tertiary butyl ether. More particularly, the invention relates to a continuous process for the reaction of tertiary butyl alcohol with methanol and purification of the methyl tertiary butyl ether containing reaction product mixture formed by the reaction.
2. Related Methods in the Field
Concern for environmental pollution and human health disorders caused by lead from exhaust gases of internal combustion engines has motivated a reformulation of automobile gasoline to remove lead containing compounds. In order to make an unleaded gasoline of the same octane number, high octane oxygenated hydrocarbon compounds have been substituted for tetraethyl lead in the automobile gasoline formula.
A number of oxygenated hydrocarbon compounds are known to have high octane numbers. In particular, methyl t-butyl ether (MTBE), ethyl t-butyl ether (ETBE), isopropyl t-butyl ether, t-amyl methyl ether (TAME) and t-butyl alcohol (tBA) are used commercially to increase the octane number of automobile gasoline. The preparation of these ethers by the catalytic addition of an alcohol to an olefin having a double bond adjacent to a tertiary carbon atom has been extensively studied. Macroreticular acid resin catalysts are the preferred catalysts for the process.
U.S. Pat. No. 5,243,091 to C. J. Kruse et al. teaches a method for preparing methyl tertiary butyl ether from methanol and tertiary butyl alcohol. Isobutylene is used downstream of the etherification reaction zone as an extractant in the purification of methyl tertiary butyl ether. Isobutylene is also reacted with methanol to yield additional methyl tertiary butyl ether.